This is a proposal to join a multicenter clinical trials research network focused on traumatic brain injury. The proposed site, the University of Maryland and its affiliated hospital system, includes the Shock Trauma Center (STC), the primary trauma center in the State which has close relations with the State EMS helicopter and ground transport systems, two rehabilitation hospitals, Kernan Hospital and the University Specialty Hospital, and community outreach programs. In the last academic year STC admitted 735 patients with traumatic brain injury, 250 were considered severe (Glasgow Coma Score [GCS] 3 to 8), 66 considered moderately injured (GCS 9 to 12), 147 were less than 21 years of age, 382 were other than white, 176 were women, and 186 patients were discharged to one of the two rehabilitation hospitals within the system. All of the proposed investigators are full-time members of the faculty of the University of Maryland School of Medicine, and members of the Department of Neurosurgery have participated in virtually every large multi-centered study of head injury since the mid 1980s, including in both phases of the NIH Traumatic Coma Data Bank. Also within the School of Medicine is the National Study Center for Trauma and Emergency Medical Services whose role is epidemiological study of traumatic injury. As specified in the LOI, the application is to include a concept protocol to study therapy in a multicenter trial. The proposed study of decompression craniotomy could be initiated in a relatively short time once the funding period begins. While this procedure is being done in some trauma centers, specific criteria have not been determined and efficacy with regard to both short and long term outcome is unknown. While the concept is simplistic it has the advantage of potentially mitigating brain swelling without hematoma or contusion, despite the specific mechanism or mechanisms of secondary injury active at any particular time during the course of the injury.